X-ray Diffraction (XRD) is a method of analyzing the crystal structure and elemental composition of samples. XRD is used in a wide variety of applications, including the manufacture of pharmaceutical compounds, and industrial characterization of cement and mining materials.
Powder samples of minerals are a practical necessity for XRD, because a very large number of different crystal orientations need to be presented to the incoming X-rays in order to produce a predictable XRD pattern. A further advantage of using powder samples of minerals is that the powder can be moved during analysis when using coarse grained materials, so that all crystalline orientations are evaluated over time. One method for obtaining such powder motion is to use convective sample cells placed under intense vibration in order to generate granular convection movement in the powder during XRD analysis.
In practice, XRD instruments require insertion of powdered samples into a sample cell. The sample cell is then placed on a sample holder, which is introduced into the instrument. After analysis, the sample cell must be replaced or fully emptied of the sample in a manner that prevents cross-contamination. U.S. Pat. No. 7,113,265 B1 discloses the automated use of vibrations to fluidize powder for loading a sample cell, and emptying it. However this patent does not propose a full automation solution for the sample loading and removal.
Previous effort of the present Applicant includes U.S. Pat. No. 8,302,477, herein incorporated by reference in its entirety for all purposes, which teaches creating the vibrational movement by means of a tuning fork, including an actuator, a resonator, a holder arm, and a balancing arm to induce granular convection in a sample during XRD analysis; however, it does not include an assembly for loading and emptying the sample conveniently.
U.S. Pat. No. 7,134,459 B2 discloses a method for preparing a mixed powder sample, including motorized vibration for fluidization, a suction port, a pneumatic blower, and a gas flow control system. However this solution is primarily for mixing powders instead of analyzing them, and uses an array of source and destination wells in place of a single sample holder.
US Pat. No. 2007/0021929 A1 discloses a computerized high-throughput method for sample delivery to instruments, including XRD. This solution is heavily dependent on technology, involving data sets, optimal formulations, robotics, and multiple sample sites, and is not practical for loading and emptying a single sample holder containing mineral powder.
Applicant's co-pending U.S. application Ser. No. 14/313,411, filed on 24 Jun. 2014 and herein incorporated by reference under 37 C.F.R. §1.57(d) in its entirety for all purposes, discloses a sample cell assembly for containing and holding samples for X-ray analysis, which is configured to be attached to a tuning fork assembly for vibrating the samples, and means of locking and unlocking said sample cell assembly. However this solution too does not include a means allowing automatic or semi-automatic loading and emptying the sample conveniently.
Considering the background information above, a simple, robust solution which accepts loose materials loaded into an inlet by the user, and automates a series of operations to transfer the sample, perform the analysis, remove the sample and clean all components that come into contact with the powder samples, would be of great economic value. XRD sample analysis would take place in less time and with more effectiveness.